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Johnson Matthey Converter Model - Case Study

The development and use of a general model for studying and predicting the distribution of elements in the high temperature processing of precious metals.

Catalytic Converter

Precious metal containing substrates for catalytic converters used in the cars

Johnson Matthey is a world leader in the production of catalysts, precious metals and speciality chemicals. The very nature of these products means that the ability to optimise the recovery of precious metals from scrap or ore is highly desirable.

For a number of years scientists at Johnson Matthey Technology Centre, in collaboration with Anglo American Platinum, have used software tools and thermodynamic databases from the National Physical Laboratory in order to gain a more fundamental understanding of key production processes. However recently it has become possible to use the NPL thermodynamic and phase diagram software, MTDATA, in a new and exciting way.

During a year-long training secondment at NPL, JM scientist Dr Hudai Kara developed a general modelling framework based on the programming interface to MTDATA. The use of MTDATA provides a rigorous and reliable way to determine the partitioning of elements between phases. Now with the addition of process specific modelling this becomes an even move powerful tool.

A readily adaptable general "converter" model has been developed to study aspects of the production of precious metal from sulphide ores, on behalf of Anglo American Platinum, and also the recycling of precious metal scrap. Although superficially these two processes appear very different they both involve the injection of oxygen into a high temperature liquid and both result in the creation of a liquid oxide phase in addition to the original liquid holding the precious metal. The real problem is how to control the removal of unwanted elements from the valuable phase without losing any value into the waste oxide. A small deviation in the composition or loss of a precious metal such as rhodium can have great economic importance.

Catalytic Converter

Screenshot of the converter simulation program

This screen shot shows Dr Kara's model is able to follow the formation of oxide and gas phases as oxygen injection proceeds and also track the composition of the original liquid phase. In addition to gaining a deeper understanding at the research centre this also opens up the possibility of taking this type of modelling directly into the plant environment and hence providing plant management and even operators with virtual real-time and ahead-of-time prediction to supplement the on-plant measurements.

The ability to quickly model processes of considerable complexity, where many elements are distributed between various high temperature liquid, solid and gas phases, gives JM and Anglo American Platinum a significant advantage in tackling the many challenges the modern high temperature materials processor faces. These range from problems specific to the precious metal industry where very close control over materials and continual sensitivity to ever changing metal prices are required to general issues such as coping with a variable feedstock, optimising the energy usage and controlling waste streams.

A key aspect of this work was the ability to use an extremely high quality and extensive database of oxide thermodynamic data. This database has been developed at NPL over a number of years via the sponsorship of an industrial consortium, of which JM and Anglo American Platinum are members, coordinated by the Mineral Industry Research Organisation. The DTI MPP Programme supported other aspects of this work at NPL.

Further details of MTDATA, the NPL Oxide Thermodynamic Database and their use in modelling real industrial processes can be obtained by contacting Hugh Davies

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Updated 7 May 2010